Questions & Answers about Mój dywan jest czysty.
Polish possessive pronouns agree in gender, case and number with the noun they modify. Dywan is a masculine singular noun in the nominative case, so it takes the masculine form mój. The other forms are:
• moja – feminine singular nominative (e.g. moja książka)
• moje – neuter singular nominative (e.g. moje okno)